Robert Mugabe at the SADC meeting of regional leaders, who called for the Zimbabwe election deadline to be pushed back. Photograph: Ferhat Momade/AFP/Getty Images

Zimbabwe's highest court has received an application from Robert Mugabe's party to delay crucial elections by at least two weeks following pressure from regional leaders.

The president has insisted he is merely abiding by a previous court order in holding general elections on 31 July. The prime minister, Morgan Tsvangirai, a longtime opponent of Mugabe and opposition leader, wants the vote to be held in September.

Zimbabwe's last elections in 2008 were plagued by violence and ultimately forced Mugabe to join a power-sharing government with the opposition.

Officials at the constitutional court said the papers submitted by Mugabe's party asked the court to review the earlier ruling that called for a vote before the end of July.

Wednesday's move comes days after southern African regional leaders met in Mozambique and pushed for an extension until 14 August so key electoral reforms and poll preparations can take place.

The justice minister, Patrick Chinamasa, said in the papers filed at the constitutional court that he was directed by a summit of the regional presidents in Mozambique to file an urgent application to postpone the elections and asked for an extension to 14 August, court officials said.

Tomaz Salomão, secretary general of the 15-nation regional, political and economic bloc known as the Southern African Development Community, or SADC, said on Tuesday the presidents had urged Mugabe and all political groups to heed their concerns over early elections. He said the SADC grouping pledged to recognise any new decision by Zimbabwe's highest court.

"If the court does not accept the appeal our task is to deploy our observers to ensure there is at least a conducive environment for elections," he said.

Tsvangirai insists new elections can be called as late as October under the nation's new constitution to allow time for democratic reforms spelled out in both the power-sharing coalition agreement and the constitution to be put into place to pave the way for a free and fair vote.

His party says a two-week extension is still inadequate to complete reforms to sweeping media and security laws, and changes in the police, military and security services, traditionally loyal to Mugabe, to ensure their impartiality.

Mugabe declared the July poll date on 13 June, saying he was obeying the ruling of the constitutional court that linked the need for elections to a month after the automatic dissolution of the Harare parliament at the end of its current five-year term on 28 June.

His announcement on the voting date meant the drafting of amendments to longstanding election laws were frozen on legal and procedural grounds.

No date was set for the appeal before the bench of nine judges at the constitutional court.